So with a copper tubing wort chiller that you immerse in the wort (as opposed to a counterflow system) where does the cold water end up after its run through the copper tubing? Is it just siphoned of into a bucket, drain, etc?

Yes it just goes down the drain...but I've read lots of ways people reuse that water...Some people run it into the washing machine and use it to do a load of wash. Use it to clean your tools....watever use you have for some good hot water. You might as well take advantage of it.

I'm just building my wort chiller now so I haven't yet experienced it, but I will try to reuse that water if possible. Think Green!

Same idea water is running in one direction and the wort runs in the other. Waste (hot water) goes down the drain.

One thing to consider is that an immersion chiller is easy to santize, just put in your boiling wort about 15 mins before the end. No worries about trub or hop debris collecting on the inside as you would with a counter flow chiller.

I constructed a wort chiller (simple immersion style), but rather than using "cold" water from the tap (in Florida, there is no such thing as cold tap water) and sending it down the drain or into the garden, I used a fountain pump in a cooler.

Consider the standard immersion coil of copper, but the inlet (cold) is fed from the pump and the outlet (hot) gets returned to the cooler where the water is cooled off again. McDonald's will set you up with a 10 lb bag of ice for $1, so I just take the cooler down there right before the brewing session.

I grew up in Ormond/DAB, now live in Lake Mary. I haven't been able to convince the wife on brewing at the house (lack of storage mostly), so I brew with a friend near downtown Orlando.

Running the iced water through the immersion chiller via a pump is very efficient in terms of bringing your wort down to pitching temp... and especially helpful in places where "cold" water is a relative term. It also helps prevent sinkholes in Wottaguy's back yard.